How to make Pulse Oximeter at Home

In our previous blog, we interfaced Pulse-Oximeter (Max30100) Module to NodeMCU. With a little bit of modification that can be upgraded to a full functioning Pulse-Oximeter. We have interfaced 0.96" I2C OLED display before. Today we made a Pulse-Oximeter using that knowledge.

Follow our previous blogs for a better understanding of the scenario.
Pulse Oximeter MAX30100 Interface with NodeMCU
OLED Display Interface with Arduino

Things we need:

• NodeMCU
• Max30100 Module
• 0.96" OLED I2C Display Module 
• Female Berg Strip Connector
• Dot Vero Board
• Soldering Kit
• Nut and Bolts 1/8"
• PVC Spacer Tube

Connection Diagram:
Now follow the diagram below to do the connections.

After the connection is done upload the code below.

Source Code:

	/*
	Controller : NodeMCU
	Display : 0.96" OLED I2C
	Sensor : MAX30100
	*/
	#include <Wire.h>
	#include <Blynk.h>
	#include <ESP8266WiFi.h>
	#include <BlynkSimpleEsp8266.h>
	#include <Adafruit_GFX.h>
	#include <Adafruit_SSD1306.h>
	#include <OneWire.h>
	#include <DallasTemperature.h>
	#include "MAX30100_PulseOximeter.h"
	/*-------------------- Timer --------------------*/
	#define REPORTING_PERIOD_MS 1000
	#define REPORTING_PERIOD_MS_1 30000
	uint32_t tsLastReport = 0;
	uint32_t tsLastReport1 = 0;
	/*-------------------- OLED --------------------*/
	#define OLED_RESET D5
	#define SCREEN_WIDTH 128
	#define SCREEN_HEIGHT 64
	Adafruit_SSD1306 display(SCREEN_WIDTH, SCREEN_HEIGHT, &Wire, OLED_RESET);
	/*-------------------- Blynk --------------------*/
	char auth[] = "lfCiyoMVb8455V_-uKbx8HVxiLWRGN1c";
	char ssid[] = "ProjectHub";
	char pass[] = "creativestudio1974";
	/*-------------------- Max30100 --------------------*/
	PulseOximeter pox;
	float BPM, SpO2;
	/*-------------------- Temp --------------------*/
	#define ONE_WIRE_BUS 2
	OneWire oneWire(ONE_WIRE_BUS);
	DallasTemperature sensors(&oneWire);
	float TEMP;
	int pinValue;
	const unsigned char bitmap [] PROGMEM =
	{
	0x00, 0x00, 0x00, 0x00, 0x01, 0x80, 0x18, 0x00, 0x0f, 0xe0, 0x7f, 0x00, 0x3f, 0xf9, 0xff, 0xc0,
	0x7f, 0xf9, 0xff, 0xc0, 0x7f, 0xff, 0xff, 0xe0, 0x7f, 0xff, 0xff, 0xe0, 0xff, 0xff, 0xff, 0xf0,
	0xff, 0xf7, 0xff, 0xf0, 0xff, 0xe7, 0xff, 0xf0, 0xff, 0xe7, 0xff, 0xf0, 0x7f, 0xdb, 0xff, 0xe0,
	0x7f, 0x9b, 0xff, 0xe0, 0x00, 0x3b, 0xc0, 0x00, 0x3f, 0xf9, 0x9f, 0xc0, 0x3f, 0xfd, 0xbf, 0xc0,
	0x1f, 0xfd, 0xbf, 0x80, 0x0f, 0xfd, 0x7f, 0x00, 0x07, 0xfe, 0x7e, 0x00, 0x03, 0xfe, 0xfc, 0x00,
	0x01, 0xff, 0xf8, 0x00, 0x00, 0xff, 0xf0, 0x00, 0x00, 0x7f, 0xe0, 0x00, 0x00, 0x3f, 0xc0, 0x00,
	0x00, 0x0f, 0x00, 0x00, 0x00, 0x06, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00
	};
	void onBeatDetected()
	{
	display.drawBitmap( 100, 20, bitmap, 28, 28, 1);
	display.display();
	}
	BLYNK_WRITE (V5)
	{
	pinValue = param.asInt();
	}
	void setup()
	{
	/*-------------------- Display --------------------*/
	if (!display.begin(SSD1306_SWITCHCAPVCC, 0x3C)) {
	for (;;);
	}
	display.clearDisplay();
	display.setTextSize(1);
	display.setTextColor(WHITE);
	display.setCursor(28, 0);
	display.println(F("Project Hub"));
	display.display();
	/*-------------------- Blynk --------------------*/
	Blynk.begin(auth, ssid, pass);
	/*-------------------- Max30100 --------------------*/
	pinMode(16, OUTPUT); //D0 INT Pin
	if (!pox.begin())
	{
	display.clearDisplay();
	display.println("POX FAILED");
	display.display();
	for (;;);
	}
	/*-------------------- Temp --------------------*/
	sensors.begin();
	}
	void loop()
	{
	Jump:
	display.clearDisplay();
	display.setCursor(28, 0);
	display.println(F("Project Hub"));
	display.display();
	pox.begin();
	pox.setOnBeatDetectedCallback(onBeatDetected);
	pox.setIRLedCurrent(MAX30100_LED_CURR_7_6MA);
	while (1)
	{
	/*-------------------- POX --------------------*/
	pox.update();
	BPM = pox.getHeartRate();
	SpO2 = pox.getSpO2();
	/*-------------------- Blynk --------------------*/
	Blynk.run();
	/*-------------------- Timer1S --------------------*/
	if (millis() - tsLastReport > REPORTING_PERIOD_MS)
	{
	/*-------------------- Blynk --------------------*/
	Blynk.virtualWrite(V7, BPM);
	Blynk.virtualWrite(V8, SpO2);
	/*-------------------- OLED --------------------*/
	display.clearDisplay();
	display.setCursor(28, 0);
	display.println(F("Project Hub"));
	display.print(" HBPM: ");
	display.println(pox.getHeartRate());
	display.print(" SpO2: ");
	display.println(pox.getSpO2());
	display.print(" Temp: ");
	display.println(TEMP);
	display.display();
	tsLastReport = millis();
	}
	if (pinValue)
	{
	sensors.requestTemperatures();
	TEMP = sensors.getTempCByIndex(0);
	TEMP = DallasTemperature::toFahrenheit(TEMP);
	pinValue = 0;
	/*-------------------- Blynk --------------------*/
	Blynk.virtualWrite(V6, TEMP);
	/*-------------------- OLED --------------------*/
	display.clearDisplay();
	display.setCursor(28, 0);
	display.println(F("Project Hub"));
	display.println("");
	display.println("");
	display.print(" Temp: ");
	display.println(TEMP);
	display.display();
	goto Jump;
	}
	}
	}

view raw Pulse-Oximeter hosted with ❤ by GitHub

Video:
Watch the video for a better understanding.

Reference:

[1] Sarkar, S., Ghosh, A., Chakraborty, M., & Mondal, A. (2024). Design, Hardware Implementation of a Domestic Pulse Oximeter Using IOT for COVID – 19 Patient. International Journal of Microsystems and Iot, 2(1), 469–475. https://doi.org/10.5281/zenodo.10629635